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Gu W, Bai Y, Cai J, Mi H, Bao Y, Zhao X, Lu C, Zhang F, Li YH, Lu Q. Hypothermia impairs glymphatic drainage in traumatic brain injury as assessed by dynamic contrast-enhanced MRI with intrathecal contrast. Front Neurosci 2023; 17:1061039. [PMID: 36816105 PMCID: PMC9932501 DOI: 10.3389/fnins.2023.1061039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Introduction The impact of hypothermia on the impaired drainage function of the glymphatic system in traumatic brain injury (TBI) is not understood. Methods Male Sprague-Dawley rats undergoing controlled cortical impact injury (CCI) were subjected to hypothermia or normothermia treatment. The rats undergoing sham surgery without CCI were used as the control. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with intrathecal administration of low- and high-molecular-weight contrast agents (Gd-DTPA and hyaluronic acid conjugated Gd-DTPA) was performed after TBI and head temperature management. The semiquantitative kinetic parameters characterizing the contrast infusion and cleanout in the brain, including influx rate, efflux rate, and clearance duration, were calculated from the average time-intensity curves. Results and discussion The qualitative and semiquantitative results of DCE-MRI obtained from all examined perivascular spaces and most brain tissue regions showed a significantly increased influx rate and efflux rate and decreased clearance duration among all TBI animals, demonstrating a significant impairment of glymphatic drainage function. This glymphatic drainage dysfunction was exacerbated when additional hypothermia was applied. The early glymphatic drainage reduction induced by TBI and aggravated by hypothermia was linearly related to the late increased deposition of p-tau and beta-amyloid revealed by histopathologic and biochemical analysis and cognitive impairment assessed by the Barnes maze and novel object recognition test. The glymphatic system dysfunction induced by hypothermia may be an indirect alternative pathophysiological factor indicating injury to the brain after TBI. Longitudinal studies and targeted glymphatic dysfunction management are recommended to explore the potential effect of hypothermia in TBI.
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Affiliation(s)
- Wenquan Gu
- Department of Radiology, Shanghai Punan Hospital of Pudong New Area, Shanghai, China
| | - Yingnan Bai
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jianguo Cai
- Department of Radiology, Xinhua Hospital Chongming Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Honglan Mi
- Department of Radiology, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yinghui Bao
- Department of Neurology, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xinxin Zhao
- Department of Radiology, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Chen Lu
- Shanghai Weiyu International School, Shanghai, China
| | - Fengchen Zhang
- Department of Neurology, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yue-hua Li
- Department of Radiology, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, Shanghai, China,*Correspondence: Yue-hua Li,
| | - Qing Lu
- School of Medicine, Shanghai East Hospital, Tongji University, Shanghai, China,Qing Lu,
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Ringer SK, Clausen NG, Spielmann N, Weiss M. Effects of hypothermia and hypothermia combined with hypocapnia on cerebral tissue oxygenation in piglets. Paediatr Anaesth 2020; 30:970-976. [PMID: 32506675 DOI: 10.1111/pan.13943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Hypothermia and its combination with hypocapnia are frequently associated with anesthesia. AIMS The goal was to investigate the effects of hypothermia and hypothermia combined with hypocapnia (hypothermia-hypocapnia) on cerebral tissue oxygenation in anesthetized piglets. METHODS Twenty anesthetized piglets were randomly allocated to hypothermia (n = 10) or hypothermia-hypocapnia (n = 10). Cerebral monitoring comprised a tissue oxygen partial pressure (PtO2 ), a laser Doppler probe, and a near-infrared spectroscopy sensor, measuring regional oxygen saturation (rSO2 ). After baseline recordings, hypothermia (35.5-36.0°C) with or without hypocapnia (target PaCO2 : 28-30 mm Hg) was induced. Once treatment goals were achieved (Tr0), they were maintained for 30 minutes (Tr30). RESULTS No changes in PtO2 but a significant increase in rSO2 (Tr0 (mean difference 8.9[95% CI for difference3.99 to 13.81], P < .001); Tr30 (10.8[6.20 to 15.40], P < .001)) were detected during hypothermia. With hypothermia-hypocapnia, a decrease in PtO2 (Tr0 (-3.2[-6.01 to -0.39], P = .021; Tr30 (-3.3[-5.8 to -0.80], P = .006)) and no significant changes in rSO2 occurred. Cerebral blood flow decreased significantly from baseline to Tr0 independently of treatment (-0.89[-0.18 to -0.002], P = .042), but this was more consistently observed with hypothermia-hypocapnia. CONCLUSIONS The hypothermia-induced reduction in oxygen delivery was compensated by lowered metabolic demand. However, hypothermia was not able to compensate for an additional reduction in oxygen delivery caused by simultaneous hypocapnia. This resulted in a PtO2 drop, which was not reflected by a downshift in rSO2 .
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Affiliation(s)
- Simone K Ringer
- Department of Clinical Diagnostics and Services, Section Anaesthesiology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland
| | - Nicola G Clausen
- Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland.,Department of Anaesthesiology and Intensive Care, Odense University Hospital, Odense, Denmark
| | - Nelly Spielmann
- Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Markus Weiss
- Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland
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Idris Z, Song Yee A, Kandasamy R, Abd Manaf A, Hasyizan Bin Hassan M, Nazaruddin Wan Hassan W. Direct Brain Cooling in Treating Severe Traumatic Head Injury. TRAUMATIC BRAIN INJURY - NEUROBIOLOGY, DIAGNOSIS AND TREATMENT 2019. [DOI: 10.5772/intechopen.84685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Parfenova H, Pourcyrous M, Fedinec AL, Liu J, Basuroy S, Leffler CW. Astrocyte-produced carbon monoxide and the carbon monoxide donor CORM-A1 protect against cerebrovascular dysfunction caused by prolonged neonatal asphyxia. Am J Physiol Heart Circ Physiol 2018; 315:H978-H988. [PMID: 30028198 DOI: 10.1152/ajpheart.00140.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Neonatal asphyxia leads to cerebrovascular disease and neurological complications via a mechanism that may involve oxidative stress. Carbon monoxide (CO) is an antioxidant messenger produced via a heme oxygenase (HO)-catalyzed reaction. Cortical astrocytes are the major cells in the brain that express constitutive HO-2 isoform. We tested the hypothesis that CO, produced by astrocytes, has cerebroprotective properties during neonatal asphyxia. We developed a survival model of prolonged asphyxia in newborn pigs that combines insults of severe hypoxia, hypercapnia, and acidosis while avoiding extreme hypotension and cerebral blood flow reduction. During the 60-min asphyxia, CO production by brain and astrocytes was continuously elevated. Excessive formation of reactive oxygen species during asphyxia/reventilation was potentiated by the HO inhibitor tin protoporphyrin, suggesting that endogenous CO has antioxidant effects. Cerebral vascular outcomes tested 24 and 48 h after asphyxia demonstrated the sustained impairment of cerebral vascular responses to astrocyte- and endothelium-specific vasodilators. Postasphyxia cerebral vascular dysfunction was aggravated in newborn pigs pretreated with tin protoporphyrin to inhibit brain HO/CO. The CO donor CO-releasing molecule-A1 (CORM-A1) reduced brain oxidative stress during asphyxia/reventilation and prevented postasphyxia cerebrovascular dysfunction. The antioxidant and antiapoptotic effects of HO/CO and CORM-A1 were confirmed in primary cultures of astrocytes from the neonatal pig brain exposed to glutamate excitotoxicity. Overall, prolonged neonatal asphyxia leads to neurovascular injury via an oxidative stress-mediated mechanism that is counteracted by an astrocyte-based constitutive antioxidant HO/CO system. We propose that gaseous CO or CO donors can be used as novel approaches for prevention of neonatal brain injury caused by prolonged asphyxia. NEW & NOTEWORTHY Asphyxia in newborn infants may lead to lifelong neurological disabilities. Using the model of prolonged asphyxia in newborn piglets, we propose novel antioxidant therapy based on systemic administration of low doses of a carbon monoxide donor that prevent loss of cerebral blood flow regulation and may improve the neurological outcome of asphyxia.
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Affiliation(s)
- Helena Parfenova
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Massroor Pourcyrous
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Alex L Fedinec
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Jianxiong Liu
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Shyamali Basuroy
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Charles W Leffler
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
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Lilla N, Rinne C, Weiland J, Linsenmann T, Ernestus RI, Westermaier T. Early Transient Mild Hypothermia Attenuates Neurologic Deficits and Brain Damage After Experimental Subarachnoid Hemorrhage in Rats. World Neurosurg 2017; 109:e88-e98. [PMID: 28951276 DOI: 10.1016/j.wneu.2017.09.109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/15/2017] [Accepted: 09/16/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Metabolic exhaustion in ischemic tissue is the basis for a detrimental cascade of cell damage. In the acute stage of subarachnoid hemorrhage (SAH), a sequence of global and focal ischemia occurs, threatening brain tissue to undergo ischemic damage. This study was conducted to investigate whether early therapy with moderate hypothermia can offer neuroprotection after experimental SAH. METHODS Twenty male Sprague-Dawley rats were subjected to SAH and treated by active cooling (34°C) or served as controls by continuous maintenance of normothermia (37.0°C). Mean arterial blood pressure, intracranial pressure, and local cerebral blood flow over both hemispheres were continuously measured. Neurologic assessment was performed 24 hours later. Hippocampal damage was assessed by hematoxylin-eosin and caspase-3 staining. RESULTS By a slight increase of mean arterial blood pressure in the cooling phase and a significant reduction of intracranial pressure, hypothermia improved cerebral perfusion pressure in the first 60 minutes after SAH. Accordingly, a trend to increased cerebral blood flow was observed during this period. The rate of injured neurons was significantly reduced in hypothermia-treated animals compared with normothermic controls. CONCLUSIONS The results of this series cannot finally answer whether this form of treatment permanently attenuates or only delays ischemic damage. In the latter case, slowing down metabolic exhaustion by hypothermia may still be a valuable treatment during this state of ischemic brain damage and prolong the therapeutic window for possible causal treatments of the acute perfusion deficit. Therefore, it may be useful as a first-tier therapy in suspected SAH.
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Affiliation(s)
- Nadine Lilla
- Department of Neurosurgery, University Hospital Wuerzburg, Wuerzburg, Germany.
| | - Christoph Rinne
- Department of Neurosurgery, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Judith Weiland
- Department of Neurosurgery, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Thomas Linsenmann
- Department of Neurosurgery, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Ralf-Ingo Ernestus
- Department of Neurosurgery, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Thomas Westermaier
- Department of Neurosurgery, University Hospital Wuerzburg, Wuerzburg, Germany
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Szczygielski J, Müller A, Mautes AE, Sippl C, Glameanu C, Schwerdtfeger K, Steudel WI, Oertel J. Selective Brain Hypothermia Mitigates Brain Damage and Improves Neurological Outcome after Post-Traumatic Decompressive Craniectomy in Mice. J Neurotrauma 2017; 34:1623-1635. [PMID: 27799012 DOI: 10.1089/neu.2016.4615] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hypothermia and decompressive craniectomy (DC) have been considered as treatment for traumatic brain injury. The present study investigates whether selective brain hypothermia added to craniectomy could improve neurological outcome after brain trauma. Male CD-1 mice were assigned into the following groups: sham; DC; closed head injury (CHI); CHI followed by craniectomy (CHI+DC); and CHI+DC followed by focal hypothermia (CHI+DC+H). At 24 h post-trauma, animals were subjected to Neurological Severity Score (NSS) test and Beam Balance Score test. At the same time point, magnetic resonance imaging using a 9.4 Tesla scanner and subsequent volumetric evaluation of edema and contusion were performed. Thereafter, the animals were sacrificed and subjected to histopathological analysis. According to NSS, there was a significant impairment among all the groups subjected to trauma. Animals with both trauma and craniectomy performed significantly worse than animals with craniectomy alone. This deleterious effect disappeared when additional hypothermia was applied. BBS was significantly worse in the CHI and CHI+DC groups, but not in the CHI+DC+H group, compared to the sham animals. Edema and contusion volumes were significantly increased in CHI+DC animals, but not in the CHI+DC+H group, compared to the DC group. Histopathological analysis showed that neuronal loss and contusional blossoming could be attenuated by application of selective brain hypothermia. Selective brain cooling applied post-trauma and craniectomy improved neurological function and reduced structural damage and may be therefore an alternative to complication-burdened systemic hypothermia. Clinical studies are recommended in order to explore the potential of this treatment.
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Affiliation(s)
- Jacek Szczygielski
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Andreas Müller
- 2 Department of Radiology, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Angelika E Mautes
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Christoph Sippl
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Cosmin Glameanu
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Karsten Schwerdtfeger
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Wolf-Ingo Steudel
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
| | - Joachim Oertel
- 1 Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine , Homburg/Saar, Germany
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Wang JM, Zhang GF, Zhou WH, Jiang ZD, Shao XM. Changes in amplitude-integrated electroencephalograms in piglets during selective mild head cooling after hypoxia-ischemia. Pediatr Neonatol 2014; 55:282-90. [PMID: 24440513 DOI: 10.1016/j.pedneo.2013.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/26/2013] [Accepted: 09/30/2013] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Amplitude-integrated electroencephalogram (aEEG) is a simplified, alternative means of monitoring cerebral function and may be more useful clinically in some situations than conventional EEG. The aim of this study is to evaluate newborn piglets as an animal model to examine the effect of selective mild head cooling (HC) on aEEG after hypoxia-ischemia (HI). METHODS Thirty-four piglets were randomly allocated to the following treatment groups: normothermic control group (NC, n = 7), selective HC control group (HC, n = 9), normothermic HI group (NHI, n = 9), and selective HC HI group (SHC-HI, n = 9). HI was induced by temporary occlusion of both carotid arteries and simultaneous reduction of the concentration of inspired oxygen to 6% for 30 minutes. Mild hypothermia (35°C) was induced after HI using a HC cap and was maintained for 24 hours. Changes in aEEG were monitored for 6 days after these treatments and the incidence of abnormalities analyzed. Physiological parameters were also measured during this period. RESULTS In the two HI groups, animals exhibited severely abnormal aEEGs [continuous low voltage (CLV), burst-suppression, or flat tracing (FT)] 20 minutes after the beginning of HI. At 2 hours, the aEEG returned to normal in most of these animals. From 12 hours to 6 days, all animals in the NHI group exhibited severely abnormal aEEGs. Fewer animals in the SHC-HI group exhibited severe abnormal aEEGs during this time period, and four out of nine (44.4%) animals had continuous normal voltage (CNV) at 6 days. CONCLUSIONS Selective mild HC decreases the incidence of severe abnormal aEEGs at late times after HI in newborn piglets.
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Affiliation(s)
- Ji-Mei Wang
- Department of Neonatology, Gynecology, and Obstetrics, Hospital of Fudan University, Shanghai 200011, China
| | - Guo-Fu Zhang
- Department of Radiology, Gynecology, and Obstetrics, Hospital of Fudan University, Shanghai 200011, China
| | - Wen-Hao Zhou
- Department of Neonatology, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Ze-Dong Jiang
- Department of Neonatology, Children's Hospital of Fudan University, Shanghai 201102, China; Neonatal Unit, Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Xiao-Mei Shao
- Department of Neonatology, Children's Hospital of Fudan University, Shanghai 201102, China.
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Zhang M, Wang H, Zhao J, Chen C, Leak RK, Xu Y, Vosler P, Chen J, Gao Y, Zhang F. Drug-induced hypothermia in stroke models: does it always protect? CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2014; 12:371-80. [PMID: 23469851 DOI: 10.2174/1871527311312030010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/06/2012] [Accepted: 11/11/2012] [Indexed: 12/19/2022]
Abstract
Ischemic stroke is a common neurological disorder lacking a cure. Recent studies show that therapeutic hypothermia is a promising neuroprotective strategy against ischemic brain injury. Several methods to induce therapeutic hypothermia have been established; however, most of them are not clinically feasible for stroke patients. Therefore, pharmacological cooling is drawing increasing attention as a neuroprotective alternative worthy of further clinical development. We begin this review with a brief introduction to the commonly used methods for inducing hypothermia; we then focus on the hypothermic effects of eight classes of hypothermia-inducing drugs: the cannabinoids, opioid receptor activators, transient receptor potential vanilloid, neurotensins, thyroxine derivatives, dopamine receptor activators, hypothermia-inducing gases, adenosine, and adenine nucleotides. Their neuroprotective effects as well as the complications associated with their use are both considered. This article provides guidance for future clinical trials and animal studies on pharmacological cooling in the setting of acute stroke.
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Affiliation(s)
- Meijuan Zhang
- Department of Neurology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15213, USA
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Cerebral oxygen metabolism in neonatal hypoxic ischemic encephalopathy during and after therapeutic hypothermia. J Cereb Blood Flow Metab 2014; 34:87-94. [PMID: 24064492 PMCID: PMC3887346 DOI: 10.1038/jcbfm.2013.165] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/15/2013] [Accepted: 08/26/2013] [Indexed: 11/09/2022]
Abstract
Pathophysiologic mechanisms involved in neonatal hypoxic ischemic encephalopathy (HIE) are associated with complex changes of blood flow and metabolism. Therapeutic hypothermia (TH) is effective in reducing the extent of brain injury, but it remains uncertain how TH affects cerebral blood flow (CBF) and metabolism. Ten neonates undergoing TH for HIE and seventeen healthy controls were recruited from the NICU and the well baby nursery, respectively. A combination of frequency domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) systems was used to non-invasively measure cerebral hemodynamic and metabolic variables at the bedside. Results showed that cerebral oxygen metabolism (CMRO2i) and CBF indices (CBFi) in neonates with HIE during TH were significantly lower than post-TH and age-matched control values. Also, cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) were significantly higher in neonates with HIE during TH compared with age-matched control neonates. Post-TH CBV was significantly decreased compared with values during TH whereas SO2 remained unchanged after the therapy. Thus, FDNIRS-DCS can provide information complimentary to SO2 and can assess individual cerebral metabolic responses to TH. Combined FDNIRS-DCS parameters improve the understanding of the underlying physiology and have the potential to serve as bedside biomarkers of treatment response and optimization.
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Liu Q, Cai Y, Lin W, Turner GH, An H. A magnetic resonance (MR) compatible selective brain temperature manipulation system for preclinical study. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2012; 5:13-22. [PMID: 23166453 PMCID: PMC3500969 DOI: 10.2147/mder.s26835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
There is overwhelming evidence that hypothermia can improve the outcome of an ischemic stroke. However, the most widely used systemic cooling method could lead to multiple side effects, while the incompatibility with magnetic resonance imaging of the present selective cooling methods highly limit their application in preclinical studies. In this study, we developed a magnetic resonance compatible selective brain temperature manipulation system for small animals, which can regulate brain temperature quickly and accurately for a desired period of time, while maintaining the normal body physiological conditions. This device was utilized to examine the relationship between T1 relaxation, cerebral blood flow, and temperature in brain tissue during magnetic resonance imaging of ischemic stroke. The results showed that this device can be an efficient brain temperature manipulation tool for preclinical studies needing local hypothermic or hyperthermic conditions.
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Affiliation(s)
- Qingwei Liu
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, NC, USA
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Cerebral blood flow and cerebrovascular autoregulation in a swine model of pediatric cardiac arrest and hypothermia. Crit Care Med 2011; 39:2337-45. [PMID: 21705904 DOI: 10.1097/ccm.0b013e318223b910] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Knowledge remains limited regarding cerebral blood flow autoregulation after cardiac arrest and during postresuscitation hypothermia. We determined the relationship of cerebral blood flow to cerebral perfusion pressure in a swine model of pediatric hypoxic-asphyxic cardiac arrest during normothermia and hypothermia and tested novel measures of autoregulation derived from near-infrared spectroscopy. DESIGN Prospective, balanced animal study. SETTING Basic physiology laboratory at an academic institution. SUBJECTS Eighty-four neonatal swine. INTERVENTIONS Piglets underwent hypoxic-asphyxic cardiac arrest or sham surgery and recovered for 2 hrs with normothermia followed by 4 hrs of either moderate hypothermia or normothermia. In half of the groups, blood pressure was slowly decreased through inflation of a balloon catheter in the inferior vena cava to identify the lower limit of cerebral autoregulation at 6 hrs postresuscitation. In the remaining groups, blood pressure was gradually increased by inflation of a balloon catheter in the aorta to determine the autoregulatory response to hypertension. Measures of autoregulation obtained from standard laser-Doppler flowmetry and indices derived from near-infrared spectroscopy were compared. MEASUREMENTS AND MAIN RESULTS Laser-Doppler flux was lower in postarrest animals compared to sham-operated controls during the 2-hr normothermic period after resuscitation. During the subsequent 4-hr recovery, hypothermia decreased laser-Doppler flux in both the sham surgery and postarrest groups. Autoregulation was intact during hypertension in all groups. With arterial hypotension, postarrest, hypothermic piglets had a significant decrease in the perfusion pressure lower limit of autoregulation compared to postarrest, normothermic piglets. The near-infrared spectroscopy-derived measures of autoregulation accurately detected loss of autoregulation during hypotension. CONCLUSIONS In a pediatric model of cardiac arrest and resuscitation, delayed induction of hypothermia decreased cerebral perfusion and decreased the lower limit of autoregulation. Metrics derived from noninvasive near-infrared spectroscopy accurately identified the lower limit of autoregulation during normothermia and hypothermia in piglets resuscitated from arrest.
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